Security tags are used commonly with articles of merchandise, particularly clothing and the like, to prevent unauthorised removal of such articles. These tags are usually securely connected to the items and an interrogation system is located at the exit to a retail store or the like which can detect the passage of a tag and initiate an alarm. Tags are also known for securing an article or item in place and providing an indication if the tag or the article becomes detached.
A variety of security tag systems are described in the prior art. WO-A-00/16284 describes a card to which a key can be securely attached via a tether which is electrically conductive so that its condition can be monitored when the card is fixed to a separate monitoring system. In another embodiment, the card is attached to a flexible bag having electrically conductive wires whose condition can be monitored so that an attempt to break into the bag can be detected. The drawback of this device is the need for permanent attachment to the monitoring system.
U.S. Pat. No. 6,002,343 discloses an electronic tag which can be affixed to an object via a resistive element whose electrical resistivity is monitored by an on-board processor with information being transmitted to a separate detection system if the monitoring indicates that the resistive element has been compromised. This leads to a more flexible system than that described above but does not address attempts which may be made by sophisticated attackers to attack the tag itself.
U.S. Pat. No. 5,367,289 discloses an electronic article surveillance tag which would typically be connected to clothing or the like and which includes a piezoelectric film which generates a voltage when subject to mechanical forces. The tag includes an alarm which is activated if the voltage exceeds a reference. This device has been developed to detect an attempt to detach the tag from the article but in fact achieves this by looking for the application of forces to the tag. The tag could be detached from the article without activating the alarm by carefully severing the connection to the article.
GB-A-2257278 describes an anti-pilferage tag including a microcircuit to enable data communication between the tag and a host computer. Although there is brief mention of some form of tamper detection, the prime purpose of the tag is to enable the location of stock to be monitored.
U.S. Pat. No. 5,099,228 describes a security tag which can be attached to an article of merchandise by means of a tack and including a sensor for sensing the presence of the head of the tack. An attempt to tamper with the tack will therefore be detected.
U.S. Pat. No. 5,955,951 discloses another type of tag/tack arrangement.
WO-A-98/15921 describes a security system for use at a transport terminal, the system including an electronic passenger tag including a memory and a wireless communication device, the memory storing a unique passenger identification code in a tamper proof manner; and an electronic luggage tag having a wire memory and a wireless communication device. In this way, the tags can be uniquely registered with one another.
U.S. Pat. No. 6,052,068 describes a vehicle identification system including a set of vehicle identification tags which are attached to vehicles and which communicate with an interrogator to enable the vehicle identification to be determined.
There is a need to improve such security tags and we have developed a new security tag which in turn leads to novel methods of use for such a security tag.
In accordance with a first aspect of the present invention, we provide a security tag for securely identifying item(s), the security tag comprising:                a. A housing;        b. A securing mechanism for securing the housing to the item(s);        c. A monitoring system for monitoring a tag status, the tag status indicating at least whether the housing and the securing mechanism have been tampered with;        d. A store for storing item data, the item data identifying the item(s); and,        e. A communication system adapted to communicate the tag status and the item data to a remote host.        
In accordance with a second aspect of the present invention, we provide a method of securely identifying and monitoring item(s), the method comprising:                a. Attaching a security tag according to the first aspect of the invention to the item(s), the security tag having:        b. Storing item data identifying the item(s) in the store; and,        c. Monitoring the tag status and/or the item data from a remote host via the communication system.        
We have realised that each security tag of the prior art suffers from one or more of a number of disadvantages and have devised a new security tag which overcomes all these disadvantages. In particular, the tag includes an on-board monitoring system so that tampering is detected immediately and not only when the tag is interrogated by a remote host; and in addition the monitoring system monitors not only the securing mechanism by which the tag is secured to an item but also the condition of the housing itself. Thus, all types of tampering relating to the tag can be detected in contrast to the prior art.
In addition, where the item or a container enclosing the item is suitable, tampering of the item or container can also be monitored.
Although the tag could be remotely powered, for example from a main supply to a GSM/satellite module connected to the tag allowing long distance communication, in the preferred arrangement, the tag includes an on-board power supply. This provides another advantage of having an on-board monitoring system in that use of power from the power supply can be minimized. In addition, any external connection could provide an access point for any person trying to defeat the system. The tag when closed during manufacture would never be reopened unless for service or during attack. Being fully enclosed it makes the system much more resistant to any attack and removes any direct electrical connection to the internal components of the tag.
In use, if the monitoring system detects tampering, it can initiate a communication with a remote host via the communications system and typically this will include information about the tag status i.e. the fact that it is being tampered with as well as item data identifying the item concerned. The provision of an on-board monitoring system enables tampering to be detected at a very early stage and to be communicated with the remote host thus enabling remedial action to be taken as soon as possible. This makes the security tag particularly suitable for use with valuable item(s) such as articles of value including coins and banknotes.
Monitoring the condition of the housing provides an early indication of an attempt to tamper with the security tag which can be communicated to the remote host. This also prevents thieves from being able to damage the tag so as to stop the remote host from detecting that item(s) have been stolen. In one example, the housing can include a conductive portion with the monitoring system being adapted to monitor the electrical properties of the conductive portion to thereby determine the integrity of the housing. Thus, for example, if somebody pierces the housing in an attempt to destroy the internal workings of the security tag, then there will be a change in the electrical properties, such as the impedance, of the conductive portion which can be detected by the housing detector.
In an alternative example, the housing includes piezoelectric material and the monitoring system is adapted to monitor the electrical potential across the piezoelectric material to determine the integrity of the housing. Again, if somebody attempts to interfere with the housing this will generally cause vibrations which will in turn cause the piezoelectric material to generate a potential. This potential can be detected by the monitoring system so that again tampering with the housing is detected.
The monitoring system preferably includes an item detector to detect the integrity of the item(s). This may not be required however if the security tag is attached to a secure container, such as a safe, or the like.
Typically the item(s) are enclosed within a conductive enclosure in which case the item detector is adapted to monitor the electrical properties of the conductive enclosure to determine the integrity of the item(s). In this case, cash (coins and/or banknotes) could be placed for example in a bag in which wires are interwoven with the bag fabric. The conductivity of the bag would then be altered if an attempt was made to pierce the bag to extract the contents. Thus, this would allow the security tag to detect any attempt to remove item(s) from the bag.
Preferably the securing mechanism comprises a conductive member for securing the housing to the item(s). In this case, the monitoring system includes a mechanism detector adapted to monitor electrical properties of the conductive member to thereby determine the integrity of the securing mechanism.
The securing mechanism can include a piezoelectric material. In this case, the monitoring system may include a mechanism detector adapted to monitor the electrical potential across the piezoelectric material to determine the integrity of the securing mechanism.
As a further option, the securing mechanism could include a fine wire film, properties of which could be monitored by the monitoring system using a RF field applied to the film.
The securing mechanism usually includes an identification mark-up which can be associated with an indication of the item(s). This allows an additional amount of security to be provided.
The housing is usually formed from a tamper resistant material such as a lamination of rubber in a reinforced plastic as this is extremely difficult to tamper with. However, other high strength impact resistant materials can also be used.
In addition to this the housing usually includes a metal cage to protect at least the store, and also any other delicate electronic components. The metal cage will act as a Faraday cage to protect any delicate components included in the tag from EMP (electro magnetic pulse) attack.
The communication system may be any one of a number of communication systems, such as radio, infra-red, inductive or magnetic communication systems. Thus, for example, the communications system may comprises a Bluetooth type radio system. Alternatively inductive loop couplings may be provided so that when the security tag is brought in the vicinity of a reader, the tag status and some data can be read out from the store via an inductive loop.
Typically the communications system is adapted to encrypt the tag status and/or the item data prior to transfer to the remote host, for example using a PKI encryption system. This prevents third parties generating their own tag status and item data to mask the tag status of the genuine tag.
The communication system is preferably adapted to communicate with the remote host system on at least one of the following occasions:                i. At predetermined time intervals;        ii. Upon request from remote host systems; or,        iii. Upon a change in tag status indicating that the security tags and/or the item(s) have been tampered with.        
It will be realised that a number of other options are available, such as allowing the communication system to communicate with the remote host every time it reaches a predetermined location, or only on one type of occasion (i-iii) mentioned above.
Conveniently, therefore, the security tag includes a location detector for detecting the location of the tag, the tag status including an indication of the tag location. This allows the location of the tag to be tracked as the item(s) are moved around.
Currently, if it is desired to transfer ownership of items from one party to another, it is necessary to actually physically move the items from the transferor to the transferee. This process can be subject to risk, particularly if the items have a high value, such as for example banknotes. Typically in these situations, the items are secured within a locked container which is then moved by a security company or the like under secure conditions.
In order to increase the security of such systems, the security companies typically use timed locks to ensure that the items cannot be removed from the container for a predetermined time interval. This may be achieved for example by locking the container in a security van in such a way that the container can only be removed at a predetermined point in time which corresponds to the time at which the driver will reach the desired destination.
In addition to this, it is now possible to track the location of the containers and the vans so that the current location of the container and hence the items can be monitored.
However, such systems suffer from the drawback that it is still possible for the items to be stolen whilst in transit. Thus, for example the container can be removed from the van forcibly, or alternatively the van can be stolen and the container removed at the correct time at a different location. Although the location of the container in the van can be tracked, it is still possible to remove the items from the container without this being detected, thereby allowing the items to be stolen.
In accordance with a third aspect of the present invention, a method of transferring the ownership of item(s) comprises:                a. Securely identifying the item(s) by attaching a security tag to the item(s), the security tag having a monitoring system for monitoring the tag status, the tag status indicating whether the security tag and/or the item(s) have been tampered with;        b. Detecting remotely the condition of the monitoring system; and        c. Causing the remote host to register a change in ownership of the item(s) when the monitoring system does not indicate a tamper condition.        
The third aspect of the present invention recognises that once the item(s) have been secured, the ownership of the item(s) can be transferred even if the item(s) are not. In addition, the item(s) can be kept under less secure conditions.
Thus, for example, a shop owner may place money taken at the shop in a suitable container and then attach a security tag, as outlined above. At this point, the cash in the container is securely identified. Ownership of the contents of the container can then be transferred to the shop owner's bank, or the like, by registering a change in ownership at the remote host. From this point, the money is effectively owned by the bank which then has responsibility for the money. However, the container remains physically at the same location.
If at any stage the item(s) or the tag is tampere en an indication of this can be transferred to the remote host, such as a central control centre, which can identify that there is a security problem. This provides the owners with full traceability of the current status of the item(s) so that the owners can be confident that the item(s) are being transferred securely.
It will be realised that as soon as ownership of the money has been transferred, the money can be credited into the shop owner's bank account, allowing the shop owner to make transactions on the account in respect of the money which is still held on the premises. This is because the bank can account for the exact location and security of the money at all times.
Should the shop owner subsequently require cash from the bank, the shop owner can then simply arrange for ownership of the money to be transferred back, allowing the shop owner to retrieve the cash from the container in accordance with the bank's instructions. Accordingly, whilst the cash has been owned by the bank for a period of time, it has never left the shop premises. This therefore allows ownership of item(s) to be transferred without the item(s) themselves having to be moved which in turn helps reduce security risks.
Although the method can be used with conventional security tags, it is particularly suitable for use with security tags according to the first aspect of the invention in view of the high security which those tags can achieve. The third aspect of the invention is particularly suitable for use with articles or documents of value such as banknotes and coins.